are you trying to get it to flow character by character?

tbh, i think doing it your way might not be the best way to go

what i would do is just attached the characters to the curve as a motion curve and play with the keyframes in the trax editor (i think its the trax editor... the one that lets you fine tune your keyframes)

more likely than not you'll need to write yourself a command to attach them all and adjust the start and end keyframe, so you aren't manually doing everything and taking days for something that you could do in an hour or so...